We have demonstrated in preliminary studies that PCP, given acutely, produces dose-related toxic and lethal effects in rats and dogs. That is, as the dose of PCP is increased, the number of rats that lose muscular coordination, and the number of rats that die, increase; also, the severity of toxic symptoms of PCP in dogs (e.g., behavioral stimulation, convulsions and death) also increases as the dose of PCP is increased. These basic dose-response studies in rats and dogs are necessary to define the doses of PCP that are to be used in subsequent studies of ascertaining the potential antidotal effects of various drugs. Moreover, our analyses of the behavioral effects of PCP in dogs reflect some important correlational aspects with regard to PCP toxicity in humans. That is, many of the human symptoms of PCP (e.g., facial grimacing, jaw snapping, blank stare, staggering, tremors, convulsions and death) are also seen in the dog following PCP administration at about the same dose levels. Additionally, we have preliminary data to indicate that PCP increases the toxicity (and lethality) of alcohol (ethanol) in rats. This would suggest that the simultaneous use of these two drugs (which apparently may be quite common in humans) would be expected to cause additive or perhaps supra-additive toxicity. Finally, we have preliminary evidence that activated charcoal can antidote the toxic lethal effects of PCP in rats and dogs, when each drug is given at about the same time by mouth. Activated charcoal is a valuable (non-toxic) drug that is commonly used in the home and in hospitals to antidote the toxic effects of many drug and poison ingestions. Additional studies in dogs and rats are ongoing to determine more fully the potential usefulness of activated charcoal as an antidote for PCP intoxication in humans.